Ball joint seal

ABSTRACT

A ball joint includes a socket and a stud having a ball end portion received in the socket and a shank projecting from the socket. An annular seal has an intermediate portion extending between first and second end portions. The second end portion of the seal has an engagement portion in sealing engagement with the shank portion of the stud. A spring is molded in the second end portion of the seal and extends for 360 degrees around the circumference of the shank portion at a location radially outward of the engagement portion. The spring has a circular array of spring fingers that extend radially inward from a main body portion and exert a radially inward directed force on the engagement portion to maintain it in sealing engagement with the shank portion.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a ball joint and, in particular, to aseal for a ball joint.

2. Description of the Related Art

A typical ball joint includes a socket and a ball stud. The ball studhas a ball end portion received in the socket and a shank portionprojecting from the ball stud. The socket supports the ball stud forpivotal movement relative to the socket with the shank portion extendingfrom the socket. The ball joint also includes a seal that has a firstend portion that seals against the socket. A second end portion of theseal seals against the shank portion of the ball stud. The seal preventslubricant from coming out of the ball joint and also prevents dirt andother items from entering into the ball joint. The second end portion ofthe seal may wear against the ball stud, but still needs to be kept insealing engagement.

SUMMARY OF THE INVENTION

The present invention is a ball joint comprising a socket defining apivot center, a bearing in the socket, and a stud having a ball endportion received in the bearing and a shank portion projecting from thesocket. The stud has a longitudinal axis extending through the pivotcenter. The bearing supports the stud in the socket for pivotal movementabout the pivot center. The ball joint further comprises an annular sealhaving an intermediate portion extending between first and second endportions of the seal. The first end portion of the seal is fixed to thesocket. The second end portion of the seal has an engagement portion insealing engagement with the shank portion of the stud. The seal includesa spring molded in the second end portion of the seal and extending for360 degrees around the circumference of the shank portion of the stud ata location radially outward of the engagement portion of the seal. Thespring has a main body portion and a circular array of spring fingersthat extend radially inward from the main body portion and exert aradially inward directed force on the engagement portion of the seal tomaintain the engagement portion of the seal in sealing engagement withthe shank portion of the stud.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present invention will becomeapparent to those skilled in the art to which the present inventionrelates upon reading the following description with reference to theaccompanying drawings, in which:

FIG. 1 is a sectional view of a ball joint constructed in accordancewith the present invention;

FIG. 2 is an enlargement of a portion of FIG. 1;

FIG. 3 is a perspective view of a spring that forms part of the balljoint of FIG. 1;

FIG. 4 is a top plan view of the spring of FIG. 3;

FIG. 5 is a sectional view of the spring of FIG. 4, taken along line 5—5of FIG. 4; and

FIG. 6 is an enlarged view of a portion of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a ball joint for supporting a firstvehicle portion for movement relative to a second vehicle portion. Thepresent invention is applicable to various ball joint constructions. Asrepresentative of the invention, FIG. 1 illustrates a ball joint 10. Theball joint 10 is located between a first vehicle portion shown partiallyat 12 and a second vehicle portion shown schematically and partially at14.

The first vehicle portion 12 may be a steering knuckle or steering yoke,for example. The first vehicle portion 12 has a cylindrical opening 16for receiving the ball joint 10. The second vehicle portion 14 may be acontrol arm or steering yoke or steering knuckle, for example. Thesecond vehicle portion 14 has a frustoconical surface that defines atapered bore or opening indicated at 18.

The ball joint 10 is generally of a conventional construction andincludes a socket 30 and a steel ball stud 40. The socket 30 is mountedin the opening 16 in the first vehicle portion 12. A mounting flange 32extends radially outward from a side wall 34 of the socket 30, spacedfrom a closed lower end 36 of the socket.

A bearing 38 is located in the socket 30. A ball end portion 42 of theball stud 40 is received in the bearing 38. The ball end portion 42 ofthe ball stud 40 is pivotable and rotatable in the bearing 38, about apivot center 43, to provide for relative movement between the firstvehicle portion 12 and the ball stud 40.

The ball stud 40 has a shank portion 50 that projects from the ball endportion. The shank portion 50 has a cylindrical first section 52centered on a longitudinal central axis 56 of the ball stud 40. The axis56 extends through the pivot center 43. The first section has acylindrical outer surface 58. The shank portion 50 also has a secondsection 60 that has a tapered outer surface centered on the axis 56. Theshank portion 50 also has a threaded end section 62.

When the ball joint 10 is assembled with the second vehicle portion 14,the tapered portion 60 of the shank 50 is fitted in the tapered opening18 in the second vehicle portion in a tight, force-fitting connection. Anut (not shown) is screwed on the threaded end section 60 of the ballstud 40 to secure the connection.

The ball joint 10 further includes a seal 70. The seal 70 extendsbetween the socket 30 and the first section 52 of the ball stud 40. Theseal 70 has a first end portion 72 connected with the socket 30 and asecond end portion 74 connected with the ball stud 40.

The seal 70 includes a seal member 80 and a retainer ring, or spring,90. The seal member 80 is made from an elastomeric material. Theelastomeric material is selected to have good flex fatigue life,puncture resistance, and abrasion resistance, etc.

The seal member 80 has a first end portion 82 fixedly connected with thesocket 30. The first end portion 82 seals against the socket 30 andforms the first end portion 72 of the seal 70.

The seal member 80 has a second end portion 86. The second end portion86 of the seal member 80 is adjacent to and connected with the shankportion 50 of the ball stud 40 in a manner described below. The secondend portion 86 of the seal member 80 forms part of the second endportion 74 of the seal 70. The second end portion 86 of the seal member80 is pivotable with the ball stud 40. The shank portion 50 of the ballstud 40 is rotatable relative to the second end portion 80 of the sealmember 80.

The seal member 80 also has a main body portion 88. The main bodyportion 88 of the seal member 80 extends between and interconnects thefirst end portion 72 of the seal 70 and the second end portion 74 of theseal. The main body portion 88 of the seal member 80 forms a main bodyportion of the seal 70 itself.

The retainer ring, or spring, 90 is molded within the second end portion86 of the seal member 80. The spring 90 is made from a plastic material,as described below. The spring 90 forms part of the second end portion74 of the seal 70, together with the second end portion 86 of the sealmember 80.

The spring 90 has an annular configuration that extends for 360 degreesaround the shank portion 50 of the ball stud 40. The spring 90 has amain body portion 92 that has a ring-shaped or annular configuration.The main body portion 92 is located on the outer periphery of the spring90.

The main body portion 92 of the spring 90 has a cylindrical outer sidesurface 94 that extends axially between parallel, annular, radiallyextending upper and lower end surfaces 96 and 98. (The terms “upper” and“lower” are used herein to describe the orientation of the spring asviewed in FIGS. 1-3 and 5, and are not limiting structurally. In thedrawings, the arrow 100 indicates an “upward” direction, and the arrow102 indicates an opposite, “downward” direction.)

The spring 90 includes a plurality of tangs, or spring fingers, orfingers 104. The fingers 104 extend radially inward from the innerperiphery of the main body portion 92 of the spring 96, in a directiontoward the axis 56. In the illustrated embodiment, thirty-six fingers104 are provided on the spring 90. A larger or smaller number of fingers104 can be provided, dependent on the diameter of the spring 90, amongother factors.

The plurality of fingers 104 includes a first plurality or group offingers that are referred to herein as “upper fingers” 106, and a secondplurality or group of fingers that are referred to herein as “lowerfingers” 108. All the upper fingers 106 are identical to each other. Allthe lower fingers 108 are identical to each other.

The upper fingers 106 are mirror images of the lower fingers 108, in atop-to-bottom manner. Thus, an upper finger 106, when viewed from abovein FIG. 5, appears identical to a lower finger 108, when viewed frombelow in FIG. 5.

The upper fingers 106 are interspersed with the lower fingers 108 aroundthe inner periphery of the main body portion 92 of the spring 90.Specifically, the upper fingers 106 are disposed in an alternatingrelationship with the lower fingers 108 around the axis 56. Each one ofthe upper fingers 106 is located between two adjacent lower fingers 108,and each one of the lower fingers 108 is located between two adjacentupper fingers 106. There is a gap between each two adjacent fingers 106,108.

Because the upper fingers 106 are configured like the lower fingers 108,the spring 90 can be molded into the seal member 80 in eitherorientation-upper end surface 96 or lower end surface 98 facing towardthe socket 12 and will function the same. This feature provides for easeof assembly.

Because the spring fingers 106 and 108 are identical to each other, oneparticular upper spring 110 finger shown in FIG. 6 is described indetail, with regard to its surfaces and the portions those surfacesdefine. The reference numerals for the surfaces and portions of thespring finger 110 are, in the drawings, sometimes used on other springfingers of the spring 90.

The finger 110 has two side surfaces 112 and 114 that extend radiallyinward from the main body portion 92 in a direction toward the axis 56.The side surfaces 112 and 114 converge in a direction toward the axis56. As a result, the finger 110 has a decreasing circumferential extent,or tapers, as it extends radially inward from the main body portion 92of the spring 90. The side surface 112 on each finger 104 is adjacentto, but spaced apart from, the side surface 114 of the adjacent finger104, to define the gap between them.

The finger 110 includes a first surface 116 that extends radially inwardas an extension of the upper end surface 96. The first surface 116 isplanar, and has an arcuate configuration centered on the axis 56, asviewed from above in FIG. 5, and as seen in FIG. 4. (Dot-dash lines areused in FIG. 6 to identify the divisions between adjacent surfaces.)

A second surface 118 extends axially from the first surface 116, in adirection perpendicular to the first surface and toward the plane of thelower end surface 98. The second surface 118 has an axial extent ofabout one third the axial extent of the outer side surface 94. Thesecond surface 118 has a radially inwardly facing cylindricalconfiguration centered on the axis 56, as best seen in FIG. 4.

A third surface 120 extends generally radially inward from the secondsurface 118. The third surface 120 has an axially bowed configurationthat is convex in the upward direction 100. The third surface 120 asviewed from above in FIG. 5, or as seen in FIG. 4, has an arcuateconfiguration centered on the axis 56.

A fourth surface 122 extends axially upward from the third surface 120,in a direction toward the plane of the upper end surface 96 and parallelto the second surface 118. The fourth surface 122 has an axial extentslightly less than that of the second surface 118, and terminates shortof the plane of the upper end surface 96. The fourth surface 122 has aradially outwardly facing cylindrical configuration centered on the axis56, as best seen in FIG. 4.

A fifth surface 124 extends radially inward from the fourth surface 122in a direction perpendicular to the fourth surface and parallel to theplane of the upper end surface 96. The fifth surface 124 is planar, andhas an arcuate configuration centered on the axis 56, as viewed fromabove in FIG. 5, and as seen in FIG. 4.

A sixth surface 126 extends axially downward from the fifth surface 124,in a direction toward the plane of the lower end surface 98 and parallelto the second surface 118 and the fourth surface 122. The sixth surface126 terminates short of the plane of the lower end surface 98. The sixthsurface 126 has a radially inwardly facing cylindrical configurationcentered on the axis 56, as best seen in FIG. 4. The sixth surface 126is the radially innermost surface of the finger 110.

A seventh surface 128 extends radially inward from the sixth surface126. The seventh surface 128 is similar to the fifth surface 124. Theseventh surface 128 is planar, and has an arcuate configuration centeredon the axis 56, as viewed from below in FIG. 5, and as seen in FIG. 4.

An eighth surface 130 extends axially upward from the seventh surface128, in a direction toward the plane of the upper end surface 96 andparallel to the sixth surface 126. The eighth 130 surface has an axialextent slightly less than that of the fourth surface 122. The eighthsurface 130 has a radially outwardly facing cylindrical configurationcentered on the axis 56, as best seen in FIG. 4. The eighth surface 130is similar to the fourth surface 122.

A ninth surface 132 extends generally radially outward from the eighthsurface 130. The ninth surface 132 has an axially bowed configurationthat is concave in the downward direction 102 and extends parallel tothe bowed third surface 120. The ninth surface 132 as viewed from belowin FIG. 5, or as seen in FIG. 4, has an arcuate configuration centeredon the axis 56.

A tenth surface 134 extends axially downward from the ninth surface 132,terminating in the plane of the lower end surface 98. The tenth surface134 has a radially inwardly facing cylindrical configuration centered onthe axis 56, as best seen in FIG. 4.

An eleventh surface 136 extends radially outward from the tenth surface134. The eleventh surface 136 is planar, and has an arcuateconfiguration centered on the axis 56, as viewed from below in FIG. 5,and as seen in FIG. 4.

A twelfth surface 138 extends axially upward from the eleventh surface136, terminating at about the level of the third surface 120. Thetwelfth surface 138 has a radially outwardly facing cylindricalconfiguration centered on the axis 56, as best seen in FIG. 4.

A thirteenth surface 140 extends generally radially outward from thetwelfth surface 138. The thirteenth surface 140 has an axially bowedconfiguration that is concave in the downward direction 102. Thethirteenth surface 140 as viewed from below in FIG. 5, or as seen inFIG. 4, has an arcuate configuration centered on the axis 56.

A fourteenth surface 142 extends axially downward from the thirteenthsurface 140, terminating at the lower end surface 98 of the main bodyportion 92 of the spring 90. The fourteenth surface 142 has acylindrical configuration centered on the axis 56, as best seen in FIG.4.

The surfaces 112-142 of the spring finger 110 define a plurality ofportions of the spring finger. The portions are not physically discrete,but are identified thus as they have specific separable functions. Thespring finger 110 includes a first cantilever portion, or outercantilever portion designated 150 in FIG. 5. The outer cantileverportion 150 extends generally radially inward, from the main bodyportion 92. The outer cantilever portion 150 is bounded or definedaxially by the first surface 116 on top and the thirteenth surface 140on the bottom.

The spring finger 110 includes an annular outer rib portion, or outerrib, designated 152 in FIG. 5. The outer rib 152 extends axiallydownward from the radially inner end of the outer cantilever portion150. The outer rib 152 is supported on the spring main body portion 92by the outer cantilever portion 150. The outer rib 152 is defined by thefirst surface 116, the second surface 118, the tenth surface 134, theeleventh surface 136, and the twelfth surface 138.

The spring finger 110 includes a second cantilever portion, or innercantilever portion designated 154 in FIG. 5. The inner cantileverportion 154 extends generally radially inward from the outer rib 152.The inner cantilever portion 154 is defined axially by the third surface120 on top and the ninth surface 132 on the bottom, and thus has a bowedconfiguration.

The spring finger 110 includes an inner rib portion, or inner rib,designated 156 in FIG. 5. The inner rib 156 extends axially both upwardand downward from the radially inner end of the inner cantilever portion154. The inner rib 156 is supported on the outer rib 152 by the innercantilever portion 154. The inner rib 156 is defined by the fourth,fifth, sixth, seventh, and eighth surfaces 122-130, respectively.

The inner rib 156 is the portion of the spring finger 110 that isfarthest radially inward. The sixth surface 126 on the inner rib 156, isthe surface of the spring finger 110 that is farthest radially inward.The sixth surface 126 is curved in a cylindrical configuration centeredon the axis 56.

The spring 90 is preferably injection molded, and preferably from aresilient plastic material. The material is selected to provide a springforce to the upper and lower fingers 106 and 108, when one part of thespring 90 is acted upon by force tending to move it relative to anotherpart of the spring.

Specifically, because the spring 90 is made from a resilient material,the inner rib 156 is resiliently movable relative to the outer rib 152,upon deformation or bending of the inner cantilever portion 154. Thus,if the outer rib 152 is held still, a radially outwardly directed forceon the inner rib 156 causes the inner cantilever portion 154 to deflect,bowing in the upward direction 100, and the inner rib 156 moves radiallyoutward toward the outer rib 152.

Similarly, because the spring 90 is made from a resilient material, theouter rib 152 is resiliently movable relative to the main body portion92 of the spring, upon deformation or bending of the outer cantileverportion 150. Thus, if the main body portion 92 is held still, a radiallyoutwardly directed force on the outer rib 152 causes the outercantilever portion 150 to deflect, bowing in the upward direction 100,and the outer rib 152 moves radially outward toward the main bodyportion 92. Because the outer cantilever portion 150 is radially shorterthan the inner cantilever portion 154, the outer rib 152 is notdeflectable as much as the inner rib 156. The primary radial deflectionin the spring 90 occurs by deformation of the inner cantilever portion154.

When the spring 90 (FIG. 2) is molded in the seal member 80, the springis substantially completely enclosed in the material of the seal member,except at one annular groove area 158 located on the second end portion86 of the seal member 80.

An engagement portion 160 of the seal member 80 is disposed radiallyinward of the spring 90. The engagement portion 160 includes threeaxially spaced lips 162 for engagement with the first section 52 of theshank portion 50 of the stud 40. The three lips 162, and the remainderof the engagement portion 160, are located radially inward of the innerrib 156 of the spring 90. The axial extent of the engagement portion 160is about the same as the axial extent of the inner rib 156.

The dimensions of the spring 90, and the dimensions of the seal member80, are selected so that there is an interference fit between theengagement portion 160 and the shank 50 when the seal 70 is fitted onthe stud 40 as shown in FIG. 2.

As one example, the shank portion 52 of the stud 40 has an outerdiameter of 23.15 millimeters. The engagement portion 160 of the sealmember 80, when in the free state, has an inner diameter of 17.5millimeters. This is less than the outer diameter of the shank portion52 of the ball stud 40. The spring 90 has am inner diameter of 22.0millimeters when in the free state.

When the seal 70 is mounted on the stud 40, the engagement portion 160including the lips 162 is, therefore, urged radially outward. This forceis transmitted to the spring 90, and the inner ribs 156 of all thespring fingers 104 are urged radially outward. The inner cantileverportions 154 of the spring fingers 104 resiliently deflect.

Because the spring fingers 104 are resiliently deflected radiallyoutward, the spring 90 exerts a radially inward directed force on theengagement portion 160 of the seal member 80. This force maintains theengagement portion 160 in sealing engagement with the shank portion 52of the stud 40. Specifically, the main body portion 92 of the spring 90,with its annular or ring-shaped configuration, provides a base againstwhich the spring fingers 104 resiliently deflect. This deflection causesthe spring fingers 104 to exert a constant, radially inwardly directedforce on the engagement portion 160 of the seal member 80. This force isexerted uniformly at all locations around the 360 degree circumferenceof the shank portion 52 of the ball stud 40, because the array of springfingers 104 extends for 360 degrees around the axis 56, with very littlespace in between adjacent spring fingers. This force maintains theengagement portion 160 of the seal member 80 in sealing engagement withthe shank portion 52 of the stud 40.

The engagement of the seal member 80 with the ball stud 40 seals inlubricant that is contained in the ball joint 10. The engagement of theseal member 80 with the ball stud 40 also prevents the ingress of anymaterial from outside the ball joint 10, such as dirt or oil.

Over the lifetime of the ball joint 10, the engagement portion 160 ofthe seal member 80 may wear. For example, the ball stud 40 may rotatewithin the seal 70, so that there is rotating or sliding contact betweenthe shank portion 50 of the ball stud, and the engagement portion 160 ofthe seal 70. Should any wear occur, the radially inward spring forceexerted by the spring fingers 104 urges the engagement portion 160farther radially inward, to maintain the engagement portion in sealingengagement with the ball stud 40. The sealing engagement between theseal 70 and the stud 40 is maintained uniformly at all locations aroundthe 360 degree circumference of the shank portion 52 of the ball stud.

From the above description of the invention, those skilled in the artwill perceive improvements, changes and modifications in the invention.Such improvements, changes and modifications within the skill of the artare intended to be covered by the appended claims.

Having defined the invention, I claim:
 1. A ball joint comprising: asocket defining a pivot center; a bearing in said socket; and a studhaving a ball end portion received in said bearing and a shank portionprojecting from said socket, said stud having a longitudinal axisextending through said pivot center; said bearing supporting said studin said socket for pivotal movement about said pivot center; said balljoint further comprising an annular seal having an intermediate portionextending between first and second end portions of said seal, said firstend portion of said seal being fixed to said socket, said second endportion of said seal having an engagement portion in sealing engagementwith said shank portion of said stud; said seal including a springmolded in said second end portion of said seal and extending for 360degrees around the circumference of said shank portion of said stud at alocation radially outward of said engagement portion of said seal; saidspring having a main body portion and having a circular array of springfingers that extend radially inward from said main body portion andexert a radially inward directed force on said engagement portion ofsaid seal to maintain said engagement portion of said seal in sealingengagement with said shank portion of said stud, said array of springfingers includes a first group of spring fingers having cantilever armsthat are bowed axially in a first direction and a second group of springfingers having cantilever arms that are bowed axially in a seconddirection opposite said first direction.
 2. A ball joint as set forth inclaim 1 wherein said engagement portion of said seal blocks engagementbetween said spring fingers of said spring and said shank portion ofsaid stud.
 3. A ball joint as set forth in claim 1 wherein said springfingers have radially inner terminal end surfaces that extend parallelto said shank portion of said stud.
 4. A ball joint as set forth inclaim 3 wherein each one of said spring fingers includes a cantileverarm that supports said terminal end surface of said spring finger forresilient movement toward and away from said shank portion of said ballstud.
 5. A ball joint as set forth in claim 1 wherein said springfingers of said first group are arranged alternately with said springfingers of said second group in said circular array.
 6. A ball joint asset forth in claim 1 wherein said second end portion of said seal isrotatable on said shank portion of said stud.
 7. A ball joint as setforth in claim 1 wherein each one of said spring fingers has an outercantilever arm extending radially inward from said main body portion, anouter rib portion supported on said outer cantilever arm, an innercantilever arm extending radially inward from said outer rib portion,and an inner rib portion supported on said inner cantilever arm.
 8. Aball joint as set forth in claim 1 wherein said spring fingers of saidfirst group being mirror images of said spring fingers of said secondgroup when viewed in axially opposite directions.
 9. A ball joint as setforth in claim 1 wherein each one of said spring fingers has acylindrical, radially innermost surface supported on said main bodyportion of said spring for movement toward and away from said main bodyportion of said spring in response to force applied to said spring. 10.A ball joint comprising: a socket defining a pivot center; a bearing insaid socket; and a stud having a ball end portion received in saidbearing and a shank portion projecting from said socket, said studhaving a longitudinal axis extending through said pivot center; saidbearing supporting said stud in said socket for pivotal movement aboutsaid pivot center; said ball joint further comprising an annular sealhaving an intermediate portion extending between first and second endportions of said seal, said first end portion of said seal being fixedto said socket, said second end portion of said seal having anengagement portion in sealing engagement with said shank portion of saidstud; said seal including a spring molded in said second end portion ofsaid seal and extending for 360 degrees around the circumference of saidshank portion of said stud at a location radially outward of saidengagement portion of said seal; said spring having a main body portionand having a circular array of spring fingers that extend radiallyinward from said main body portion and exert a radially inward directedforce on said engagement portion of said seal to maintain saidengagement portion of said seal in sealing engagement with said shankportion of said stud, each one of said spring fingers has an outercantilever arm extending radially inward from said main body portion, anouter rib portion supported on said outer cantilever arm, an innercantilever arm extending radially inward from said outer rib portion,and an inner rib portion supported on said inner cantilever arm.
 11. Aball joint as set forth in claim 10 wherein said engagement portion ofsaid seal blocks engagement between said spring fingers of said springand said shank portion of said stud.
 12. A ball joint as set forth inclaim 10 wherein said inner rib portions on said inner cantilever armshave radially inner terminal end surfaces that extend parallel to saidshank portion of said stud.
 13. A ball joint as set forth in claim 10wherein said array of spring fingers includes a first group of saidspring fingers arranged alternately with a second group of said springfingers, said spring fingers of said first group being mirror images ofsaid spring fingers of said second group when viewed in axially oppositedirections.
 14. A ball joint as set forth in claim 11 wherein each oneof said spring fingers has a cylindrical, radially innermost surfacesupported on said main body portion of said spring for movement towardand away from said main body portion of said spring in response to forceapplied to said spring.
 15. A ball joint comprising: a socket; a bearingin said socket; a stud having a ball end portion received in saidbearing and a shank portion projecting from said socket, said stud beingpivotal relative to said socket; and an annular seal having anintermediate portion extending between first and second end portions ofsaid seal, said first end portion of said seal being connected with saidsocket, said second end portion of said seal extends around said shankportion of said stud; said seal including a spring molded in said secondend portion of said seal and extending around said shank portion of saidstud; said spring having a main body portion and having a circular arrayof spring fingers that extend radially inward from said main bodyportion and exert a radially inward directed force on said seal andmaintain sealing engagement with said shank portion of said stud, saidspring fingers have radially inner terminal end surfaces, each of saidterminal end surfaces being formed as a portion of a cylinder having acentral axis which is coincident with a central axis of said stud.
 16. Aball joint as set forth in claim 15 wherein each one of said springfingers includes a cantilever arm that supports said terminal endsurface of said spring finger for resilient movement relative to saidshank portion of said ball stud.
 17. A ball joint as set forth in claim15 wherein said array of spring fingers includes a first group of springfingers that are bowed in a first direction and a second group of springfingers that are bowed in a second direction opposite said firstdirection.
 18. A ball joint as set forth in claim 17 wherein said springfingers of said first group are arranged alternately with said springfingers of said second group in said circular array.
 19. A ball joint asset forth in claim 15 wherein said second end portion of said seal ismovable relative to said shank portion of said stud.
 20. A ball joint asset forth in claim 15 wherein said second end portion of said seal is atleast partially disposed between said terminal end surfaces on saidspring fingers and said shank portion of said stud.
 21. A ball joint asset forth in claim 15 wherein at least a portion of each of said springfingers is exposed at said second end portion of said seal.
 22. A balljoint comprising: a socket; a bearing in said socket; a stud having aball end portion received in said bearing and a shank portion projectingfrom said socket, said stud being pivotal relative to said socket; andan annular seal having an intermediate portion extending between firstand second end portions of said seal, said first end portion of saidseal being connected with said socket, said second end portion of saidseal extends around said shank portion of said stud; said seal includinga spring molded in said second end portion of said seal and extendingaround said shank portion of said stud; said spring having a main bodyportion and having a circular array of spring fingers that extendradially inward from said main body portion and exert a radially inwarddirected force on said seal and maintain sealing engagement with saidshank portion of said stud, said spring fingers have radially innerterminal end surfaces, each of said terminal end surfaces being formedas a portion of a cylinder having a central axis which is coincidentwith a central axis of said stud; each one of said spring fingers has anouter cantilever arm extending radially inward from said main bodyportion, an outer rib portion supported on said outer cantilever arm, aninner cantilever arm extending radially inward from said outer ribportion, and an inner rib portion supported on said inner cantileverarm, each of said terminal end surfaces being disposed on one of saidinner rib portions.
 23. A ball joint as set forth in claim 22 whereinone of said cantilever arms supports said terminal end surface of saidspring finger for resilient movement relative to said shank portion ofsaid ball stud.
 24. A ball joint as set forth in claim 23 wherein saidarray of spring fingers includes a first group of spring fingers thatare bowed in a first direction and a second group of spring fingers thatare bowed in a second direction opposite said first direction.
 25. Aball joint as set forth in claim 24 wherein said spring fingers of saidfirst group are arranged alternately with said spring fingers of saidsecond group in said circular array.
 26. A ball joint as set forth inclaim 23 wherein said second end portion of said seal is movablerelative to said shank portion of said stud.
 27. A ball joint as setforth in claim 23 wherein said second end portion of said seal is atleast partially disposed between said terminal end surfaces on saidspring fingers and said shank portion of said stud.
 28. A ball joint asset forth in claim 23 wherein at least a portion of each of said springfingers is exposed at said second end portion of said seal.